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首页> 外文期刊>Journal of Applied Polymer Science >Thermal Residual Stresses in Freely Quenched Slabs of Semicrystalline Polymers:Simulation and Experiment
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Thermal Residual Stresses in Freely Quenched Slabs of Semicrystalline Polymers:Simulation and Experiment

机译：自由淬火半结晶聚合物板中的热残余应力：模拟和实验

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Thermal residual stresses in freely quencled semicrystalline polymer slabs were calculated based upon the modifications of the Indenbom theory for inorganic glasses and linear viscoelasticity. These modificationns were introduced to include the influences of crystallization on mechanical and physical properties of the polymer during free quenching.The nonisothermal crystallization kinetic model due to Nakamura et al.was employed to calculate the variations of crystallinity. In the case of the Indenbom theory, a polymer during crystallization was assumed to undergo an abrupt transition from an ideal plastic state to an elastic state upon the completion of crystallization.In the case of linear viscoelasticity, the Morland-Lee constitutive equation was utilized with the effect of crystallization on the time-temperature dependent shear relaxation modulus taken into account.The Spencer-Gilmor P- V - T equation of state was emploved to model the specific volume changes during crystallization and used to determine the local thermal loding that results from inhomogeneous densifications and gives rise to the thermal residual stresses in the slabs.Based on the above theoretical work, the thermoelastic and thermoviscoelastic models were developed, and the corresponding numerical simulation schemes were formulated to calculate the residual thermal stresses in freely quenched slabs of semicrystalline polymers. Free quenching experiments were carried out under various colling conditions using isotactic polypropylene. The layer removal method due to Treuting and Read was utilized to measure the residual thermal stresses.The simulated and measured results were then compared.The effects of quenching conditions and crystallization on the development of residual thermal stresses were evaluated.It has been found that both coolant types and coolant temperature have significant effects on residual tehrmal stresses. In caontrast, initictial temperature of the polymer melt shows a slight influence only.
机译：基于对无机玻璃的Indenbom理论的修正和线性粘弹性，计算了自由淬火的半结晶聚合物板中的热残余应力。引入这些改性剂包括结晶对自由淬火过程中聚合物的机械和物理性能的影响。采用Nakamura等人的非等温结晶动力学模型来计算结晶度的变化。在Indenbom理论的情况下，假定结晶过程中的聚合物在完成结晶后会从理想的塑性状态突然转变为弹性状态;在线性粘弹性的情况下，使用Morland-Lee本构方程考虑了结晶对时间-温度相关的剪切弛豫模量的影响。采用Spencer-Gilmor P-V-T状态方程来模拟结晶过程中的比容变化，并用于确定由在上述理论工作的基础上，建立了热弹性和热粘弹性模型，并建立了相应的数值模拟方案，以计算半固态聚合物自由淬火平板的残余热应力。 。使用全同立构聚丙烯在各种冷却条件下进行自由淬灭实验。利用Treuting和Read去除层的方法来测量残余热应力，然后将模拟结果和测量结果进行比较，评估了淬火条件和结晶对残余热应力发展的影响。冷却剂类型和冷却剂温度对残余热应力有很大影响。顺带一提，聚合物熔体的初始温度仅显示出轻微的影响。

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